My Ps3 Keeps Freezing? Help!?

alright so i have the older ps3's the fat one and it works perfectly fine when i played mw2 for 25 days amd now since i got black ops ive played it nd i like this game all of a sudden one day my ps3 says data is corrupt and its going to restore im like alright nd i click restore same msg keeps popping up and i manage to get out of there by doing the management screen whatever its called and i click restore ps3 , okay so now i put black ops and play it and after 2-3 games it works perfectly fine after the 3 game finishes the pinwheel loading shows up and stops so now im like WTF and i click the eject button and 1 minute later the disc finally comes out but the strange part is that right before the disc is going to come out i hear the people in the lobby talking so im like WTF and then the disc comes out so im like maybe its the disc so i try another disc that has been in its case the whole time and my ps3 says its dirty and to clean it so i do and same thing happens , so open my ps3 and clean it frm dust and clean the laser and then put black ops in and same crap happens so now im like pissed off now cuz im good at that game and if any1 knows what i can do to make my ps3 work again